The human eye has an ability to perceive a wide dynamic range from very dark to extremely bright. In this respect, the human eye outperforms most modern cameras. As a result, cameras, which have a limited dynamic range, need to adapt to different scenarios, such that more light is captured in dark scenarios while the light is limited in bright scenarios. This is referred to exposure control.
FIG. 1 illustrates an experimental setup 100 where a camera 102 takes a photo of a pattern 110. The pattern 110 comprises a white square 112, a light grey square 114, a dark grey square 116 and a black square illuminated by a light source (not shown).
A first output pattern 120 shows the captured output image where the camera 102 uses a shutter speed of 1/20. It can be seen that the white square 112, the light grey square 114 and the dark grey square 116 are captured as pure white and only the black square 118 is captured in light grey. The first output pattern is too bright and therefore referred to as overexposed.
In contrast, a second output pattern 130 shows the captured output image where the camera 102 uses a shutter speed of 1/500. It can be seen that the black square 118, the dark grey square 116 and the light grey square 114 are captured in black while only the white square 112 is captured in dark grey. The second output pattern is too dark and therefore referred to as underexposed.
A third output pattern 140 is correctly exposed and the optimal shutter speed of the camera is 1/100.
While the correct exposure can be found by a manual process, it is difficult to accurately determine the optimal exposure automatically.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.